integration/grpc/src/main/java/io/seata/integration/grpc/interceptor/client/ClientTransactionInterceptor.java
<filename>integration/grpc/src/main/java/io/seata/integration/grpc/interceptor/client/ClientTransactionInterceptor.java/*
 *  Copyright 1999-2019 Seata.io Group.
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package io.seata.integration.grpc.interceptor.client;

import io.grpc.CallOptions;
import io.grpc.Channel;
import io.grpc.ClientCall;
import io.grpc.ClientInterceptor;
import io.grpc.ForwardingClientCall;
import io.grpc.ForwardingClientCallListener;
import io.grpc.Metadata;
import io.grpc.MethodDescriptor;
import io.seata.common.util.StringUtils;
import io.seata.core.context.RootContext;
import io.seata.integration.grpc.interceptor.GrpcHeaderKey;

/**
 * @author ychag@example.com
 */
public class ClientTransactionInterceptor implements ClientInterceptor {

    @Override
    public <ReqT, RespT> ClientCall<ReqT, RespT> interceptCall(
        MethodDescriptor<ReqT, RespT> method,
        CallOptions callOptions,
        Channel next) {

        String xid = RootContext.getXID();
        return new ForwardingClientCall.SimpleForwardingClientCall<ReqT, RespT>(next.newCall(method, callOptions)) {

            @Override
            public void start(Listener<RespT> responseListener, Metadata headers) {
                if (StringUtils.isNotBlank(xid)) {
                    headers.put(GrpcHeaderKey.HEADER_KEY, xid);
                }
                super.start(new ForwardingClientCallListener.SimpleForwardingClientCallListener<RespT>(responseListener) {
                    @Override
                    public void onHeaders(Metadata headers) {
                        super.onHeaders(headers);
                    }
                }, headers);
            }
        };
    }
}
